winslow



\No Model.)

S. W. WINSLOW. BUPPING MACHINE.

Patented Sept. 18, 18194.

L /fd 442./

A "UNITED STATESPAJTENT Ormese SIDNEY WV. WINSLOW, OF BEVERLY,MASSACHUSETTS, ASSIGNOR-TO SIDNEY b W. W'INSLOV,TRUSTEE.

BuFFlNc-MACHINE.

SPECIFICATION forming part of Letters Patent No. 526,137, datedSeptember 18, 1894.

I Application filed December 26, 1893.l Serial No.4941692- (N mOdBL) Toall whom t may concern:

Be it known that I, SIDNEY W. WINsLow,

of Beverly, county of Essex, State of Massaf chusetts, have inventedanlmprovement in Buing-Machines, of which the following description, inconnection with the accompanying drawings, is a specification, likeletters on the drawings representing likevparts.

My invention is embodied in a bufng machine of the class shown inLetters Patent No. 221,647, dated November 11, 1879, to Winslow andFifield, and relates especially to the pad or foot which receives andsupports the abrasive material or cover by which the abrading action visproduced. Various constructions have been adopted for the purpose ofmaking the pad yielding so that the abrasive surface will accommodateitself to the surface being operated upon, such pads having for mostpart been composed of felt, or rubber, or felt and rubber combined.

The object of the present invention is to produce a pad having greateriiexibility and resilience than those'heretofore employed so that theabrasive material will readily accommodate itself to the surface beingoperated upon without producing undue pressure at any part of thesaidsur'face so as to cause heating, and the said pad also has greatresilience or power of resuming its original shape and conditions whenthe pressure upon it has been removed, and furthermore maintains anexpansive pressure on theinner surface of the abrasive cover, therebykeeping the said cover in a state of tension.

The pad forming the subject of the present invention is composed of ahollow circular chamber the upper and under walls of which are flexible,being preferably composed of soft rubber and said walls being also airtight so that the chamber can be iniiated or distended by pneumaticpressure, the pad thus formed being very flexible and elastic.

The invention further consists in the combination of a pad of the kinddescribed (that is, one having a resilient margin and being of anexpansible nature) with an abrasive pad cover having a permanentlyinturned flange adapted to be placed on said pad and held thereon by theexpansive pressure of the latter on the interior of the said flanged padcover.

Figure lis a transverse section of a pad and spindle Atherefor embodyingthis invention; Fig. 2, a plan view of the pad detached; Fig. 3, anunder side view of the end -of the spindle; Fig. 4, a transversevertical section showing a modified construction of the pad, and spindleor pad holder, and Fig. 5 a side elevation partly in section showing padof the kind shown in Fig. 1 with an abrasive cover applied thereto saidcover being shown in section.

The pad forming the subject of this inven tion is in the form of acircular hollow chamber having iexble upper and under walls a, a2, whichare united together around their peripheries, thus forming a circularflat chamber having a thin iexible edge. When an abrasive cover isapplied to a pad of this kind said cover having a working force lyingupon the under face of the pad, and an attaching portion or portionsextending over the periphery of the pad and lying upon the upper surfacethereof, expansion of the pad will maintain a strain or pressure uponthe abrasive cover tending to hold'its working surface in a state oftension and thus opposing the tendency of the cover to grow loose orwrinkle in the operation of the machine, and thereby rendering the covermore durable and effective than is the case when no such expansivepressure or tension is applied to it. The walls of the chamber besidesbeing flexible are air tight being preferably composed of soft rubberalone, or soft rubber vulcanized to'a suitable fabric when necessary togive it greater strength. The said chamber is provided with an air inletpassage d controlled by a stopper e shown as a hollow screw plug whichwhen screwed down in its socket tightly closes the inlet passage d. Thesaid pad may be connected with its actuating spindle f in any suitableor usual manner. As shown in Figs. l, 2, and 5, the said pad is providedwith fastening studs or projections g shown as short screws screwed intoa metallic ring g2 vulcanized'into the upper wall a2 of the pad. Thespindle f is provided at its lower end o tion of the machine.

tions g have been passed through the holes f3, thus securely locking thepad to the spindle f, which isshown as hollow so that a tube can bepassed through the same as shown in dotted lines at h Fig. 1, to engagewith the z5 screw plug e so that the pad can be inated or deflated ifdesired without disconnecting it from the spindle, as would be desirableif it were permanently attached thereto.

It is not essential that the pad should4 be 2o fastened to the spindlebya clamp or fastening device that connects the two directly together,but a pad of this kind may be used with a spool or pad holder of thekind shown in Fig. 4, in which case the pad is inclosed in a iexiblecover t', which may be the abrasive cover or not, the said cover beingclamped between the cones f1, f20, of the spool in the usual manner,said spool being substantially the same as shown in Letters Patent No.

3o 221,647, `before referred to.

In some cases it is desirable to provide a somewhat stiffer support forthe abrasive material than that afforded by the flexible wall a of theair chamber and the internal pneu- 3 5 matic pressure against the same,and in such cases the pneumatic pad may have its under wall ci coveredwith a layer of felt as shown at am, such` construction aording greaterresiliency than when a pad composed wholly of 4o felt, or of felt withsolid rubber is used, being also somewhat less yielding than apad of theconstruction shown in Fig. 4.

The felt is a non conductor of heat and it is advantageous, and in somecases almost essential, to provide a layer of non-conducting materialbetween the rubber wall of the pad and its abrasive cover to protect theformer as well as thematerial operated upon from being heated or damagedin the opera- The felt furthermore is only slightly extensible andconsequently with the layer of felt or equivalent non-conductingnon-stretching material between the working face of the pad cover andthe pad,

5 5 the tendency of the latter to bulge or convex with internal pressureis diminished and the expansive action is thrown towards the margin ofthe upper wall of the pad where :it acts upon the pad cover near theperiphery 6o thereof, thus tending to draw the working face of the padcover tight over the supporting face of the pad and to take up anylooseness of the pad cover resulting from its softening and stretchingin the operation of the machine. A pad of this kind may be used with anysuitable form of abrasive covering.

For example, the cover t' shown in Fig. 4, by which the 'pad is fastenedto the spool or holder may if desired have its under surface of abrasivematerial being such a pad as shown in Patent No. 227,839, to Rogers,dated May 18, 1880, or likethe one shown in patent to Andreu, No.238,201, March 1, 1881, and as before stated the said cover t' may bemerely employed to fasten the pad to the holder, and the abrasive covermay then be applied to and secured upon the said pad in any suitablemanner.

While the invention so far as the novel features of the pad areconcerned is not limited to any specific form of pad cover, an expansiveor inflated pad is adapted to co-operate with a cover having apermanently inturned flange such for example as the cover shown in saidRogers Patent N o. 227,839, or such for example as shown in Fig. 5 ofthe present application, wherein the abrasive cover 7c has a permanentlyinturned flange 7a2 which engages with the upper wall of the pad whichlatter thus presses against the internal surface of the pad cover andits flange so as to hold the same securely thereon.

By having both the upper and under walls a, a2, of the pad chamberflexible and yielding, the entire marginal portion of the pad is elasticor resilient and can yield with relation to the spindle or pad holder,thus affording a more perfect accommodation of the pad to the surfacebeing operated upon, than would be the case if the entire upper wallwere rigid or substantially so, and the accommodation of the pad to thesurface being operated upon had to be provided wholly by the yielding ofthe under surface, or of the under wall,against the internal airpressure.

If found necessary the expansive pressure in the pad may be changed atany time by permitting some of the contained air to escape or byintroducing more air, and it is obvious that if air escapes by leakageor otherwise it can be replaced as may be found necessary.

A pad adapted to exert an expansive or elastic outward pressure asherein described, in conjunction with an abrasive cover having attachingportions extending over the edge and lying upon the top of the pad, willoperate to maintain a tensile strain upon the said pad cover as beforestated, and thus to hold the said cover in a strained or tense conditionas it tends to soften and grow loose in wear, thus rendering itmore-effective, and durable than is the case when it is permitted tobecome loose and wrinkled.

I claim- 1. A pneumatic pad for a bufling machine composed of ahollowflexible walled chamber provided with an air inlet opening combined witha tubular spindle and means for connecting the pad with the spindle withits inlet opening accessible through the bore of the spindle,substantially as described.

IOO

IIO

` ble circular upper and under walls connected around their peripheriesand an air inlet to said chamber whereby it may be inflated and itswalls. distended bypneumatic pressure, substantially as described.

3. The combination of a flexible-walled inflated pad with an abrasivecover applied thereto, and a layer of non-conducting material interposedbetween the working face of the pad cover and the pad, substantially asdescribed.

4f. The combination of a flexible-walled pad adapted to be inflated;with an abrasive pad cover having a portion extending over the peripheryof the pad; an actuating spindle; and a clamp for fastening said portionof the pad cover, said spindle being tubular whereby said pad may beinflated while the pad cover inclosing the' same is held by said clamp,substantially as described.

5. The combination of the pad or foot having an elastic or resilientmargin with a removable abrasive pad cover having a permanently inturnedilange adapted to be placed upon the said `pad and held thereon by theexpansive pressure of the .latter against the interior of the liangedpad cover, substantially as described.

6. The combination of a pad or foot for a bufiing machine composed of ahollow, iiexible-walled, circular chamber adapted to be inflatedorexpandedxby pneumatic pressure, with a removable abrasive cover having a.permanently inturned'flange to engage with lthe marginal portion ofsaid pad, the said cover being held upon the pad by the pressure of thelatter against the interior of the iianged cover, substantially asdescribed.

' 7. The combination of a pad cover having an abrasive working surfaceand a permanently inturned ange, with an expansive pad adapted to beinserted between the working portion and flange of the said lpad cover,and to maintain a pressure in the interior surface of the latter,substantially as and for the purpose described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

SIDNEY W. WINSLOW.

Witnesses:

Jos. P. LIvERMoRE, M. E. HILL.

